Multistage fracturing and effective isolation during stimulation is critical to the successful and efficient mining of resources. Further, effective isolation is needed for water shut-off. Existing isolation methods include, for example, cementing, which has limited effectiveness in horizontal wells due to leak-off during the cementing operation or while the cement is setting up and can be detrimental or even catastrophic to establishing isolation. Also, while cementing may be more effective in a vertical well, it may not be optimal for wells having a liner. Further, it is known that refracturing can be an effective resource recovery practice, e.g., over long time intervals In some cases, refracturing has been done three to four times during the life of a vertical producing well, however this is not possible in horizontal wells where you have only one chance with conventional state of the art hydraulic fracturing. Wells with poor cement jobs will make restimulation of specific intervals nearly impossible.
Another known isolation method includes the placement of packers on either side of an isolation location or in some cases multiple locations at the same time. A hydraulic-set mechanical packer such as the RockSeal II can provide differential pressure ratings in a variety of downhole environments. An exemplary hydraulic-set mechanical packer includes two solid hydro-mechanical rubber sealing elements that are hydraulically set on either side of a fracture to create a seal. Similarly, reactive element packers (REPs), e.g., swellable water and oil packers, have also been used as isolation or compartmentalization devices. Generally swellable packers are affixed (pre-swell) to the outside of pipe which is run into the well and are able to increase in size due reaction with one or more fluids in the well bore over an extended period of time. Mechanical packers may provide an advantage over cement due to the ability to remove the packers for secondary recovery and refracturing operations. But mechanical packers, even REPs, are limited in their ability to create a perfect seal due to the imperfect contours of the well bore walls. Further, hydraulic-set mechanical packers include moving parts, which introduced inefficiencies and the possibility for breakdown into the system.
Accordingly, there is a need in the art for an improved system and method for effectively isolating sections of a wellbore.